A collapsible buttstock with automatic deployment has a housing with an opening providing clearance for a buffer tube. Rods slidably couple through respective openings in the housing; the rods each having a hollow cavity accommodating biasing structure for exerting a biasing force against a respective attachment member. A locking element has locking blocks, each engaging a respective one of plural notches on the rods, for locking the rods to an operator support buttstock element, each of the locking blocks comprising a tapered surface. A release trigger with a contoured step engages the tapered surfaces of the locking blocks. When the release trigger is moved, the contoured step engages the tapered surfaces to push locking blocks away from engagement with the notches on the rods, thus allowing the biasing member in each rod to push the respective rod and the operator support buttstock element away from the housing.